Fig. 1
From: Factors associated with regularity and length of menstrual cycle: Korea Nurses’ Health Study
Associations of reproductive, lifestyle, and occupational factors with menstrual cycle irregularity in 9335 participants of the Korean Nurses' Health study. METs, metabolic equivalents. Compared to regular cycles defined as ≤ 7-day variability between cycles. Adjusted for age (years), age at menarche (≤ 12, 13, 14, or ≥ 15 years), parity (nulliparous, 1, or 2+), body mass index (kg/m2), vigorous physical activity (none or tertiles), and alcohol consumption (0, < 5, 5– < 15, or ≥ 15 g/day). Lines above and below the point estimates are 95% confidence intervals. The reference group is represented by simple black circle without confidence intervals